低温超饱和气体渗碳对316L奥氏体不锈钢力学性能的影响  

Effects of Low Temperature Supersaturation Gaseous Carburization on Mechanical Properties of 316L Austenitic Stainless Steel

作　　者：姜勇[1,2] 李洋[1,2] 张显程[3] 巩建鸣[1,2] 

机构地区：[1]南京工业大学机械与动力工程学院,南京211816 [2]南京工业大学极端承压装备设计与制造重点实验室,南京211816 [3]华东理工大学机械与动力工程学院,上海200237

出　　处：《中国表面工程》2018年第1期32-38,共7页China Surface Engineering

基　　金：国家自然科学基金(51475224);江苏省高校自然科学研究重大项目(14KJA470002);江苏省普通高校研究生创新计划(KYZZ16_0234)~~

摘　　要：采用低温超饱和气体渗碳技术对316L奥氏体不锈钢进行表面强化,测量了渗碳层沿深度方向的碳含量、残余应力及纳米硬度分布。通过单轴拉伸试验,测量了渗碳层表面开裂伸长率,计算了断裂韧性,并采用分离法研究了低温超饱和气体渗碳表面强化层的平均抗拉强度。结果表明,经470℃,30h低温超饱和气体渗碳处理后,奥氏体不锈钢表面形成一层厚度约30μm的表面渗碳强化层,渗碳层表面碳质量分数高达约2.4%,纳米硬度达到12.6 GPa,残余应力达到-2.2 GPa;渗碳层表面断裂韧性约19 MPa·m^(1/2),断裂应变约1.5%;渗碳层平均抗拉强度为1.4 GPa;渗碳层在提高材料整体抗拉强度的同时,降低了屈服强度和伸长率。Surface hardening of 316L austenitic stainless steels （ASSs） was conducted by low temperature supersaturation gaseous carburization （LTSGC）. Carbon content, residual stress and nano-hardness of a LTSGC layer were measured along the depth direction. The plastic strain of the crack initiation on the surface of LTSGC layer was measured by uniaxial tensile tests, and the fracture toughness and average tensile strength of the LTSGC layer were calculated, Results show that a diffusion carbon layer of 30 μm is formed near the surface of 316L after carburizing at 470 ℃ for 30 h. The surface carbon content of the LTSGC layer is up to 2.4%. The nano-hardness of the lager reaches 12.6 GPa, and the compressive residual stress is about -2.2 GPa. The surface fracture toughness and fracture elongation of LTSGC layer surface are about 19 MPa·m^1/2 and 1.5%, respectively. The average ultimate tensile strength of the carburizing layer is about 1.4 GPa. The ultimate tensile strength of the samples treated by LTSGC increases while its yield stress slightly decreases.

关 键 词：奥氏体不锈钢 低温超饱和气体渗碳 残余应力 纳米硬度 抗拉强度 

分 类 号：TG156.8[金属学及工艺—热处理]